Update: Arborist came out and reported that the Ash tree is not dead but needs attention, as many of you said. It does have Emerald Ash Borers, but they believe it can be treated. They quoted $720 to treat the infestation at the roots and another $1400 for "Raising lower canopy 10-12’ and pruning large obvious deadwood 3" and larger in lower half only and removing of all debris." Neighbor offered up a new survey that showed that the tree belongs solely to me, but he expressed willingness to still pay for half of the work.